Cable connection for brushes



V. C HAMISTER.

CABLE CONNECTION FOR BRUSHES.

APPLICATION FILED JUNE 2.1919.

1,41 2,079. Patented Apr. 11, 1922.

[NVENTOR v. 1:. mmsrzn W UNITE STATE E T O ICE-1 VICTOR CARL H AMISTER, O1 CLEVELAND, OHIO, A SSI GNOR T0 NATIONAL CARBON cum. oommc'non non BRUSHES.

' Application filed June 2,

To all whom it may concern:

Be it known that I, Vrcron C. HAMISTER, a citizen of the United States, residing at Cleveland in the county of Cuyahoga and State of hio, have invented a certain new and useful Improvement in Cable Connections for Brushes, of which the following is a full, clear, andexact description.

This invention relates to brushes for dynamo electric machines, and more particu-' larly to cable connections for the same.

There are various forms of cable connections for brushes, a common one involving the cable or pigtail down from the top of the brush, and to drill a considerably larger" hole from one side of the brush, until thethe use of solder as a retaining medium. In

this type of connection it is the usual prac-. tice to drill a small hole a little larger than two holes join. The cable is then passed through the small hole and one end pressed somewhat loosely into the large cavity. Solder is next added on top ofthe cable in the cavity until the remainder of the cavity is substantially filled flush with the sides of the brush. With this arrangement the solder runs out whenever the brushes become overheated in use, as is quite frequently the case. There being nothing to cause the cable to adhere to the brush, it soon comes out of the cavity and the connection is therefore ruined. In my improvement the solder is applied in such a way that the brush can be repeatedly overheated without the solder running out, and therefore the brush will stand great overloads without in any way impairing thegood connection between the brush and cable. The manner in which my improvement is brought about will now be the cable compacted into position.

Fig. 3 is a section of a brush showing the method of soaking the solder into the cable to 'oin it to the brush.

ig. 4' is a cross section on line 44 of Fig. 2 after the pin has been inserted.

My improvement could be used in various ways, but I have by way of example shown it in connection with the usual type of brush previously referred to.

Specification'of Letters Patent. Patnted Ap r sll 1919. Serial No.'301,195.

A small hole 1 is, drilled in the'brush 2 and then a larger hole 3 is drilled down until it intersects thehole 1. The bottom of the cavity is then copper plated as indicated at 4 and a cable 5 is assed through the hole 1 and out through t e cavity 3. The end of the cable is frayed out by untwisting the the cavity against the copper coating, as shown at 7 in Fig. 2. A suitable size chunk a suitable flux for cop'per,'and a sourceof heat, such as an oxy-hydrogen flame 9, is caused to melt the solder "I and the flame is played on the solder until it flows into and through the compacted portion of thecable strands. 5 The flame is then removed and the 1 I solder permitted to cool. a To further increase the solidity and con.-

joomramr, me, a conrom'rron or NEW-YORK. I l I strands 6 as shown, and these are then tamped or otherwise compacted down into ductivity of the connection, I sometimes 1 f drill a small hole through the compacted copper wires and a portion of the brush, into" which I drive an escutcheon pin 3' of brass or other metal. This pin, however, may be omitted when desired.

By causing the solder to run down in between the strands and against the copper coating 4, all of the small cavities are filled up and the platingis firmly soldered to the adjacent strands. There is, however, no excess of solder utilized to hold the cable in position, and all 0i it is firml held in place by capillary action. There ore, after the solder is once in position, the brush could be inverted and the molten solder would not run out.

I have found that a brush connection of this type is far superior to the ordinary solder connection where the solder is laced on top of the end of the cable 7 to su stantially fill thespace indicated at 10 in Fig. 3. The resistance is exceedingly low in this .type of connection, and a brush can-be repeatedly overloaded to the point where the solder melts .from the excessive heat gencellent service on all electric motors, even those repeatedly subject to overload, in which connection it has heretofore been considered impracticable to use soldered cables on brushes.

While my invention involves the soaking of the solder'down, in between the dense mass of strands and onto the copper plating beneath, it of course would be permissible to fill the remainder of the cavity 3 in Fig. 2 with solder or cement after the interstices between the strands have been filled. This would add nothing to the pro rties of the connection however, and if ad itional solder were used in this way, the surplus would be shaken out when melted from overload, just as in the prior types of connections. However, the solder permeating the stranded mass 7 will stay in position and resolder the connection as soon as it cools down.

While I have shown a preferred form of heating the solder by a flame 9, it of course is possible to heat the solder in other ways,-

to cause it to permeate the stranded mass, and my invention is not to be limited to any particular mode of heating.

Having described my invention, what I claim is:

1. The method of attaching a stranded flexible conductor to a carbon brush that comprises formin in said brush intersecting holes of di erent transverse sections, plating at least the bottom of the hole having the larger section, inserting the end of said conductor through the smaller of said such strands and to join such compacted mass to said plating.

2. A brush for dynamo electric machines,

such brush having intersecting holes of dif- .45

ferent cross-sectional areas, a copper coatin at the bottom of the larger hole, a strand flexible conductor extending through the smaller hole and having its end disposed in the other hole, the strandsof such end being untwisted and compacted against said copper coating, solder in the spaces between such compacted strands and between such strands and said coating, and a securing pin passing through a portion of said brush and said compacted strands.

3. A brush for dynamo electric machines, such brush having intersecting holes, a metal coating in one of said holes, a stranded cable extending through one of said holes and having its end disposed in the other hole adjacent said coating, the strands of said ends being untwisted and compacted against said coating, and solder in the spaces between such compacted strands and between said strands and said coating.

In testimony whereof, I hereunto afiix my signature.

VICTOR CARL HAMISTER. 

